Process for the obtainment and multiplication of color photographic proofs and products relating thereto



L. DUFAY Feb. 10,1931. 1,792,418

PROCESS FOR THE OBTAINMENT AND MULTIPLICATION OF COLOR PHOTOGRAPHIC PROOF AND PRQDUCTS RELATING THERETO Filed April 23, 1923 LWGIIZ-f L Juf Patented Feb. 10, 1931' UNITED STATES PATENT OFFICE LOUIS DUI'AY, or vnasmnns, more, assienon, BY mun assrenmnn'rs, 1'0

rmenss FOR. THE

TRUST LTD, 0! LONDON, ENG-LAND, A CORPORATION OF GREAT OBTAINHEN'I. AND MULTIPLIGATION OF COLOR PEOTOGRAIHIC PROOFS AND PRODUCTS BELATmG THERE'IO Application fled April 88, 1988, Serial Io. 834,185, and in France Kay 18, 1828.

I. of a very; thin transparent or translucent It has been proposed to usea transparent film provided, on each of its faces, with a layer of positive emulsion, and to place negatives taken simultaneously through colored selecting screens, one on each of the sensitive layers of the film, and to print the said layers. In order to prevent the light which impresses one of the sensitive layers from acting upon the opposite layer through the film supporting the layers, ithas also been proposed to color the said film.

The present invention relates to an im- 5,

.provedprocess for preventing the light which impresses one of the sensitive layers from acting upon the opposite layer, and this without having to color the supporting film. For this purpose, the sensitive layers themselves are colored with an-inactive coloring material which can be eliminated when washing the proof, this coloring'm'aterial being ored screens being applied on each of the emulsions to permit of their exposure and printing with light.

As intimated the film forming the subject matter of the invention is composed of two layers of positive emulsion b--c separated from each-other by a thin transparent layer a.

' These layers b0- present this essential particularity that it will be impregnated with an inactinic colouring material. The colcuring materials for that purpose may be derivatives of anilin, they must-have a high dyeing power for gelatin, have no action onthe sensitiveness of the silver salt and they must be automatically eliminated by simple washing in pure water, such for instance as tartrazine. H

' On such sensitive layers, it will be possible to obtain on the-obverse or reverse, simultaneously or successively, difi'erent positive images, or corresponding to differently se-v lected negatives, since each of the elements of the double sensitive layer will form a screen opposite the other, the light rays having impressed one of the sensitive layers .not

being able to impress the sub-jacent, owing.

to the presence of the inactinic colouring material. v p

Of course, the two elements of the double sensitive layer can be dyed in two diflerent iilactinic colours, one of the elements in yellow for instance, the other inorange or in reen.

After development and fixing in the usual manner of the double image, the washing will eliminate from the layer the soluble inactinic colouring material. 7

The photographic images are obtained on the double sensitive layer by a single de velopment. I

Of course, the duration of the development will vary according at it is desired to obtain a proof visible by reflection or a proof adapted to be projected or examined by transparency. In the first case, the development will be stopped as soon as the black image will appear by reflection in all its details, on the contrary it will be carried out to the fullest extent in the second case.

At this moment, one will thus have on one and the same support a double black silver image each of the two layers of which can be subsequently coloured 1n the desired tint by a suitable toning in the known manner. By a judicious choice of the toning tints adopted for each ofthe two elementsof the double layer, one will obtain by optical fusion, aninfinite variety of colourations and a practically satisfactory reproduction of the photographed colours. The tint of the tonin 's will of course be varied according to the e ect to be produced or to the nature of the photographed subject.

The coloured proof thus obtained will then be finished if it is intended for projection or. examination by transparency 5 if it is intended to be examined by reflectmn, it

will be laced, in the wet state on a reflecting sur ace such as a sheet of couched or sized paper of any tint for instance with which it will immediately become integral and will contract u on drying a perfect adherence. The proo obtained may be caused to adhere on any support, wood, ivory, metal, porcelain, etc.

What I claim as my invention and desire to secure by Letters Patentis In a process for the reproduction of colorv photographs on a transparent film bearing only one sensitive layer on each of its faces, impregnating the sald sensitive layers wlth tartrazine, applying simultaneously corresponding negative plates on each of the sensitive layers, exposing the film and said negative plates to light, subsequently washing the film so as to eliminate the tartrazine contained in the said layers and difierently coloring said layers.

In testimony whereof I aflix m%signature.

LOUIS UFAY. 

